This invention relates to a hose consisting of a thermoplastic liner hot melt adhesively bonded to a fabric casing and to a method of making same, and is more particularly directed to such an assembly which is especially useful for fabricating a flat or collapsible hose.
Collapsible hoses lay flat when not in use, but inflate or radially enlarge when in use to pass water or other fluid under pressure. A collapsible hose may be compactly wound on itself to save storage space and facilitate handling. Collapsible hoses currently available on the market take several different structural forms made by several different manufacturing processes.
For example, collapsible hose assemblies used in domestic gardening often have a plastic liner and outer casing connected together only by their end hose fittings. In such structure, if one layer becomes twisted relative to the other through stretching, growth, or the like, water under pressure traveling through the hose will be partially or fully blocked. This blockage may cause the inner tube to rupture, resulting in a leak or even a potential explosion. Also, when woven fabric is used as the casing material, a tear, break, or other flaw in the fabric may cause it to unravel or become enlarged during filling and emptying of the hose. This in turn may result in the inner plastic liner forming a bubble or distorted enlargement, which eventually may cause the layers to separate or break or result in other damage to the hose, making the assembly unusable.
Another collapsible hose useful for domestic gardening is made from unlined polyvinyl chloride. However, such hose is rather expensive, heavy and bulky.
Lined fire hoses are also collapsible. Some fire hoses are made by vulcanizing the liner to the casing. These vulcanized hoses are relatively costly, heavy and bulky, and are made by a fairly slow vulcanization manufacturing process. Other fire hoses have a urethane liner bonded to the casing by a cross-linking or chain extending adhesive. These adhesives are applied to the liner in liquid form and then dried without curing by solvent or freezing systems. The liner with dried cross-linking or chain extending adhesive is then inserted into a casing and inflated with hot steam or oil to provide heat and pressure to adhesively connect the liner to the casing. This type of lined hose is expensive and time consuming to manufacture, and may lack uniformity in bond because some curing of the adhesive may occur in drying or insertion. Moreover, the pressurized expansion of the liner distorts and stresses the liner material and thins the liner wall at the interstices of the fabric.
A collapsible plastic hose assembly embodying the present invention is utilized by a hot melt adhesive bond joining the inner thermoplastic liner to the outer casing. This hot melt adhesive bond may be formed by one or more adhesive beads running the entire length of the inner liner tube and outer casing. When the casing is a woven fabic, the adhesive may become partially imbedded in the fabric to improve the bond and strengthen the fabric. This hot melt adhesive bond is achieved through preferred process steps of extruding a thermoplastic tubular liner and hot melt adhesive through a common die to form localized longitudinally extending adhesive beads on the extruded tubing, cooling and flattening the liner tubing with adhesive, inserting the cooled adhesive beaded liner into the casing and subjecting the liner and casing to localized heat and pressure to melt the adhesive and chemically and physically bond the tubing and casing together upon subsequent cooling.